Automatic type element changing mechanism for single element typewriter

ABSTRACT

Type element changer mechanism for selectively interchanging type elements on a single element typewriter to provide a plurality of type fonts, selectively changeable under the control of a control unit allowing a typewriter having a memory and/or control unit to print several type fonts without manual changing of the type elements.

United States Patent Noell et all 51 Feb. 29, 1972 [54] AUTOMATIC TYPE ELEMENT CHANGING MECHANISM FOR SINGLE ELEMENT TYPEWRITER Newton G. Noel]; Donald C. Roller, both of Lexington, Ky.

Inventors:

International Business Machines Corporation, Armonk, NY.

Dec. 31, 1969 Assignee:

Filed:

App]. No.:

US. Cl '.197/18, 197/52, 197/50 Int. Cl. ..B4lj 23/04, B4lj l/ 60, B4 lj l/32 Field of Search l97/48, 52, 18, 53

References Cited UNITED STATES PATENTS 3/1967 Young ..l. ..l97/ l8 X 3,356,198 5/ l 966 Michelotti .1.111; l97/48 3,334,721 8/1967 Hickerson..... l97/50 3,027,988 4/ 1962 Tackett .197/52 3,307,677 3/1967 Frank et a1 ..l97/52 2,969,864 l/l96l Holgate 197/52 Primary Examiner-Robert E. Pulfrey Assistant Examiner-Stephen C. Pellegrino AttorneyHanifin and Jancin and E. Ronald Coffman [57] ABSTRACT Type element changer mechanism for selectively interchanging type elements on a single element typewriter to provide a plurality of type fonts, selectively changeable under the control of a control unit allowing a typewriter having a memory and/or control unit to print several type fonts without manual changing of the type elements.

6 Claims, 9 Drawing Figures KEYBOARD Min/Yum CONTROL RESPONSIVE comm INVENTORS NEWTON G. NOELL DONALD C, ROLLER BY a Ja JV.

ATTORNEY PAIENTEDFEB 29 I972 SHEET 2 [IF 4 AUTOMATIC TYPE ELEMENT CHANGING MECHANISM FOR SINGLE ELEMENT TYPEWRITER FIELD OF THE INVENTION This invention relates to the automated selection and changing of working elements and more specifically to the automated and controlled interchanging of type elements in a single background element typewriter.

BACKGROUND OF THE INVENTION In present-day useage, typewriters such as the IBM SELEC- TRIC Typewriter IBM Magnetic Tape Selectric Composer, Magnetic Tape/Selectric Typewriter, and the IBM Magnetic/Card Selectric Typewriter have a need for the changing of type elements, commonly referred to as type balls, to allow flexibility in the typed material being produced. The IBM Selectric Typewriter is more fully disclosed in US. Pat. No. 2,919,002, entitled Selection Mechanism for a Single Printing Element Typewriter." The computer and magnetic tape control of single element printing typewriters is more fully disclosed in U.S. Pat. No. 3,417,379, entitled Clocking Circuits for Memory Accessing and Control of Data Processing Apparatus. The magnetic control of a proportional escapement printer is more fully disclosed in US. Pat. No. 3,404,766, entitled Variable Spacebar Mechanism for Automatically Operated Proportional Escapement Printer." All of the above patents are assigned to the same assignee as this application. Selectric is a trademark of the International Business Machines Corporation, Armonk, New York.

An example of this need is when a mathematical equation is required in the text of a document and the symbols used in the mathematical equation are not on the type ball being used for the textual material. Thus, a change is required from a first to a second type ball.

Another example is the changing within a particular document from a roman type font to an italic type font. In the past, it has been necessary for the automatically controlled typewriter to stop while an operator removes the roman type ball and replaces it manually with an italic type ball and then restarts the machine. This partially defeats the advantages of a totally automated and self-controlled typewriter in that an operator is required to perform a function only a very small part of the time but must be present most of the time in order to properly utilize the machine.

The control console of the above machines are capable of controlling functions in the typewriter in addition to those already controlled and therefore only needs an apparatus for automatically changing the type ball upon command from the control console in order to make the above type of machines fully automatic with respect to several different type fronts.

OBJECTS OF THE INVENTION It is an object of this invention to provide an automated type ball changer for a typewriter having a single moveable type element.

It is an additional object of this invention to provide automatic impression control setting in response to a selected type head which has been automatically inserted into the type head carrier.

It is a further object of this invention to provide an automated process for changing type elements on an automatically controlled typewriter.

It will be apparent to one skilled in the art that the above objects are accomplished by the incorporation into a typewriter having a single type element, a mechanism having an indexable carousel which contains additional type elements and control mechanism for removing and replacing selected type elements in response to signals from the control unit. In addition, an impression control setting mechanism is provided to change the impression set in response to the selected type ball, in order that the final typed copy will have uniform impressions regardless of the type font selected for any portion of the copy. Further, an improved type head removal mechanism is provided to simplify the removal and replacement of type heads automatically and under the control of the control unit.

DRAWINGS FIG. 1 is an exploded rear perspective of the changer drive and timing mechanism.

FIG. 2 is a perspective of the operative end of the plunger arm and plunger mechanism.

FIGS. 3a and 3b are frontal views of the ratchet latch mechanism in different stages of the operation.

FIG. 4 is a frontal perspective of the carousel, indexing control mechanism and selector controls.

FIG. 5 is a plan view of the indexing control mechanism.

FIG. 6 is a frontal perspective of the impression set mechanism and controls.

FIG. 7 is a frontal perspective of the impression set lever and link taken at line 77 in FIG. 6.

FIG. 8 is a planar view of the impression set latch mechanism.

DETAILED DESCRIPTION The basic structure to which the improvement is added is a single element typewriter 10 shown in FIG. 1. FIG. 1 is an exploded view, to better illustrate the parts; some of the parts appear to be unassociated and disconnected, but one skilled in the art will recognize that the parts will be associated and connected in the operating apparatus.

A drive motor 12 provides the motive power for the headchanging apparatus. Motor 12 drives worm 14 through an interconnecting shaft 13. Worm 14 intermeshes with worm gear 16 to impart rotary motion of the worm gear 16. Worm gear 16 is fixedly attached to the input portion or driving portion of cycle clutch 20. The cycle clutch 20 may be any conventional single cycle clutch. The output shaft of cycle clutch 20 is attached to a combined gear/cam 22 by shaft 23. The gear portion of the gear/cam 22 meshes with a second gear/cam 30 which is mounted on a second shaft 31. Fixed to the gear/cam 22 is a crank arm 24 having a crankpin 25 in the extended end of the crank arm 24. The crankpin 25 rides in the scotch yoke slider slot 26 of scotch yoke slider 27. The scotch yoke slider 27 is fixedly attached to the support shaft 28. Support shaft 28 extends through two slide bearing surfaces 32 of slide bracket 34. Attached to the uppermost end of the support shaft 28 is plunger arm 36.

Referring to FIG. 2, plunger arm 36 carries on its cantilevered end a ratchet mechanism 38 which in turn is comprised of torsion spring 40, ratchet 42, and ratchet follower 44, in addition to ratchet latch 46 and ratchet deflector 48. One end of torsion spring 40 is attached to a portion of plunger arm 36. The second end of the torsion spring 40 is attached ratchet follower 44 to provide a resistance when ratchet follower 44 is moved in an upward direction. The ratchet follower 44 is slideably mounted in a guide slot 50 formed into a protrusion 52 extending from the plunger arm 36. Ratchet 42 is pivotably mounted on the follower 44 so that it may move in a vertical direction with follower 44 and at the same time rotate in response with ratchet deflector 48 and ratchet latch 46. Attached to protrusion 52 is plunger push-pull bracket 54. Plunger push-pull bracket 54 has a plunger stub 56 and puller arm 58.

Referring to FIG. I, slide bracket 34 is attached to a support frame 60 at the side of the typewriter 10. Support frame 60 also supports plate 62 extending horizontally out over the typewriter 10. To provide an indexable storage and positioning means a carousel 66 is provided. Pivotably mounted upon plate 62 is a carousel disc support 64 and carousel disc 66. Carousel disc 66 is rotated by a drivebelt 68 and pulley 70. Pulley 70 is interconnected internally through disc support 64 to carousel disc 66. The belt extends through an aperture 72 and over idler pulleys 74 downward to drive pulley 76 which in turn is driven by worm gear 16.

To provide an installation and removal capability, a plunger 100 is provided. The construction of plunger 100 is best illustrated by FIG. 2. Plunger 100 is constructed of a tube 102 with a plunger rod 104 extending through the central opening of plunger tube 102. Plunger rod 104 is offset so that its uppermost end will engage follower flange 45 when plunger arm 36 is moved downward.

A cap plate 106 is rigidly mounted on the upper end of plunger tube 102. The edges of cap plate 106 extend outward in all directions from the periphery of plunger tube 102 to provide a lip entirely around a tube. A coil spring 108 is coaxially disposed around plunger tube 102 and acts between the upper surface of carousel disc 66 and the lower surface of cap plate 106 to keep plunger tube 102 in its raised position except when cap plate is being acted upon by plunger stub 56.

On the lower end of plunger tube 102 is mounted a stabber blade 110. Stabber blade 110 has on its two lateral edges cam surfaces 112. Surrounding the lower end of plunger end 102 is guide cap 114. The guide cap 114 is rigidly attached to plunger tube 102. On both sides of stabber blade 110 are situated two moveable removal lugs 116. Lugs 116 are connected to the lower end of plunger rod 104 which extends from the top to the bottom of the plunger tube 102. Type element 118 is provided with a slot 120 in its top. Slot 120 is oriented transversely to the arm of the retainer spring 117 to allow the stabber blade 110 carn surfaces 112 to engage and spread the retainer spring 117 contained within the type element 118. In this application transverse is intended to include any orientation perpendicular or deviating from the perpendicular to the arms that will permit the arms of retainer spring to be forced apart by the stabber blade 110. The retainer spring 117 normally grasps the type element carrier lug 122 in the groove 124 surrounding the lug 122. Type element carrier lug 122 is provided with a slot 126 to allow stabber blade 110 to fully enter the slot 120 in type element 118 when the type element 118 is carried on the carrier lug 122.

Referring to FIG. 1, follower lever 140 is pivotably attached to support frame 60. The cam surface 142 engages follower lug 144 and thus'the movement of follower lever 140 is dependent upon the movement of the scotch yoke slider 27. Two linkages 146, 154 extend form the upper portion of follower lever 140. Link 146 extends laterally to a lever 148 which in turn is rigidly connected to and controls the position of tilt arm 150, which has mounted on one end of the arm 150 tilt pulley 152 of the typewriter 10. The position of tilt pulley 152 controls the tilt of the type element.

An automatic impression set mechanism is provided to change the position of the impression control when type balls are changed. This helps in producing a uniform copy.

A second link, 154, interconnects the upper end of follower lever 140 and bellcrank 156. Bellcrank 156 is pivotably supported upon the underside of support plate 62, best illustrated in FIG. 6. Connected to the output arm of bellcrank 156 is link 158 which interconnects bellcrank 156 and bellcrank 160. Bellcrank 160 is pivotably mounted and extends through support plate 62 to operate output arm of the bellcrank 160 on the top of support plate 62. Connected to the output arm of the bellcrank 160 is a link 162 which is connected to the upper arm of impression set lever 180. Pivotably supported upon impression set lever 180 is impression set link 182. Impression set set link 182 is connected to latch mechanism 184 at the top of impression set lever 180. Latch mechanism 184 is more clearly shown in FIG. 8. Impression set trigger 186 is adjustably mounted on carousel disc 66. One impression set trigger 186 is located on the carousel disc 66 for each storage position and each type element 1 18.

Referring now to FIG. 8, impression set trigger 186 is capable of engaging knockoff cam 188. Knockoff cam 188 is pivotably mounted on latch pawl 190 and is held in its normal position by a torsion spring 192. Latch pawl 190 has a latch tooth which engages a latch 196 holding it in position. Latch 196 is fixedly attached to the uppermost end of impression set link 182 so that the two elements may rotate together.

To grasp the impression control lever and move it to another position a hook 183 is provided in the lower end of the impression set link.

Referring to FIGS. 7 and 8, the lower end of impression set link 182, referred to as impression set link hook 183, is shown in position with respect to the impression control 198. Set link hook 183 engages and captures impression control 198 in the recess and thus is able to overcome the resistance to movement it exhibits.

Referring to FIG. 6, reset cam 200 is shown attached to support plate 62 and positioned so that the cam surface 202 is located at a radial distance from the pivot point 204 equal to the radial distance from the pivot point to the lower end of impression set link 182.

CAROUSEL INDEX CONTROL MECHANISM To control the indexing of carousel disc 66, an indexing control mechanism is provided and illustrated in FIGS. 4 and 5. Located at equidistant points around the periphery of the carousel disc 66 are stop tabs 250. These stop tabs 250 are positioned so that when the carousel disc is stopped by the index control mechanism, the corresponding type element plunger is directly positioned above the home or change position for the type element carrier. Also on the periphery of carousel disc 66 are a plurality of control lugs 252. These control lugs are positioned equidistantly around the periphery of carousel disc 66. Also, the control lugs are positioned in several discreet planes, one lug 252 to each plane in the vertical dimension or thickness dimension of the carousel disc 66.

To control the position at which carousel disc 66 stops,

several solenoids 254 are provided. Selector solenoids 254 cooperate with latch leaves 256. Latch leaves 256 in turn cooperate and block the rotary movement of pawls 258. Pawls 258 are spring loaded by torsion springs 260 to continuously urge the pawls 258 to rotate in a counterclockwise direction when view from above. Pawls 258 have a notch 262 which in turn engages the lip 264 on latch lever 266. Latch lever 266 is pivotably supported by retainer pin 268. Stop pawl 272is attached to latch lever 266 by a stop pawl spring 274. Stop pawl 272 is restrained to one direction of movement with respect to latch lever 266 by slots 273 and stop pawl slot 276. Stop pawl 272 engages cam lever 278 when in its displaced position. Connected to the output of cam lever 278 is a link 284 leading to the control of cycle clutch 20.

Stop pawl 272 has an arm 286 and lug 288 extending outwardly from carousel disc 66. Extending upwardly from below is stop pawl reset lever 290 which is pivotably supported on a suitable frame member 291. Connected to stop pawl reset lever 290 above the lever pivot point 292 and below the upper end is reset cable 294. Reset cable 294 is connected to cam follower 296, best seen in FIG. 1. Cam follower lever 296 is spring biased by follower lever spring 298 to hold cam follower lever 296 in contact with one or both cams on gear cam 22 and 30.

Also cooperating with cam 30 is bellcrank 300. Bell crank 300 is held in its inoperative position by latch 302. The output arm of bellcrank 300 is spring biased by spring 304 and connected to cables 306 and 308 which in turn connect to the carriage return mechanism of typewriter 10 and to an index inhibit mechanism and carrier return key lever of typewriter 10 respectively.

DESCRIPTION OF OPERATION In describing the operation of the type head changing mechanism, an example will be used of changing from a roman type font to an italics type font. For the sake of the example it is assumed that the typewriter is typing a page of material in the roman type font and it is desired that the type font be changed to italics for a short period of time, two or three words, and then be returned to the roman type font. To initiate the change cycle after the last word is typed in the roman type font, a command from the control console activates latch solenoid 303 or a manual command may be given from a keyboard key lever which acts on latch 302, or acts to energize solenoid 303. In either event, latch 302 pivots away from bellcrank 303, allowing bellcrank 300 to pivot around is pivot point 301 and allowing the follower surface 299 to ride up against cam 30. As bellcrank 300 rotates in a counterclockwise direction when viewed from the left end of the typewriter 10, cables 306 and 308 move in response to the output arm of bellcrank 300. Cable 306 activates the carriage return mechanism of typewriter to cause the carrier and type element 118 to return to its home or change position which is defined as that position immediately under the type element plunger which is in operative position in respect to the plunger arm of the changer mechanism. Link 308 is connected to an index inhibit mechanism which prevents the platen 11 of the typewriter 10 from indexing automatically as the carrier is returned to the home position. When the carrier returns to the home position, this is indicated by overbank of the margin rack which is interconnected with the cycle clutch activating mechanism. Cycle clutch is then activated and the output shaft 23 responds to the rotary motion of the input portion of cycle clutch 20. The input portion of cycle clutch 20 is driven by worm gear 16 which in turn is driven by worm 14 and motor 12. The output of single cycle clutch 20 is transferred to gear cam 22. The crank arm 24 which is attached to gear cam 22 rotates with the gear cam 22 and the pin 25 riding in scotch yoke slider slot 26 causes the scotch yoke slider 27 to reciprocate in a vertical direction, in response to the rotary movement of crank arm 24. At the end of a cycle and at the beginning of each cycle, crank arm 24 is in a raised position and hence scotch yoke slider 27 is also at its upper limit of travel. As the single revolution of gear cam 22 and crank arm 24 begin, scotch yoke slider 27 is moved downward, causing support shaft 28 to which scotch yoke slider 27 is attached to move downward also. Scotch yoke follower lug 144 acts against follower lever 140 at lever cam surface 142, to pivot follower lever 140. As the scotch yoke slider 27 and scotch yoke slider lug 144 move downward, follower lever 140 is rotated away from typewriter 10. The motion of follower lever 140 is transmitted through link 146 to tilt lever 148. Tilt lever 148 through its pivot shaft rotates tilt arm 150 in a clockwise direction when viewed from the rear of the typewriter l0. Tilt pulley 152 is attached to the uppermost portion of tilt arm 150 and is moved outward from the right end of typewriter 10 when viewed from the rear. By moving tilt pulley 152 to the right, the tilt mechanism of the carrier causes the type element 118 to change position, becoming vertical. As can be seen from the above, the type element 118 is set in a vertical or erect position through the described linkages and levers to facilitate removal of the roman font type ball. At this point in the cycle, crank arm 24 is approximately horizontal. As the scotch yoke slider 27 has moved downward in the response to the rotary motion of crank arm 24, support shaft 28 has likewise moved downward.

As plunger arm 36 is moved downward by support shaft 28 moving downward, the cantilevered end of plunger arm 36 moves the ratchet mechanism indicated generally as 38 downward. This action can best be seen in FIG. 2. During this downward movement, the first element to encounter any resistance is follower flange 45 of follower 44. Follower flange 45 encounters the upper end of plunger rod 104 and is effective in displacing plunger rod 104 downward. Torsion spring 40 prevents follower 44 and follower flange 45 from moving with respect to plunger arm 36 during this portion of movement. At the time that follower flange 45 has fully depressed plunger rod 104, plunger push-pull bracket stub 56.will encounter the cap plate 106 and force the entire plunger 100 downward acting against the force of coil spring 108. At this time, the stabber blade 110 which is attached to the bottom extremity of plunger tube 102 moves toward the slot 120 in type element 118. Removal lugs 116 extend laterally from the side surfaces of stabber blade 110 and ride in a slot in the stabber blade. Removal lugs 116 are attached to the lower extremity of plunger rod 104 and move in response to the movement of plunger 104. The lugs at thispoint in the operating cycle are extended downward in response to the downward movement, previously described, of plunger rod 104. As the stabber blade 110 enters the stabber blade slot 120 of type element 118, the stabber blade cam surfaces 112 cam apart or spread the arms of type element retainer spring 117. This forces the arms of retainer spring 117 out of the peripheral groove 124 of type element cam carrier lug 122. The friction of the arms of spring 117 against the edges of the stabber blade 110 retains the type ball 118 on the stabber blade 110. To allow the stabber blade 110 to fully enter type element 118, a carrier lug slot 126 is provided in type element carrier lug 122, providing the required clearance. As removal lug 116 encounters the uppermost surface of type element 118, the removal lugs 116 are forced upward with respect to the stabber blade 110 and hence plunger rod 104 is forced upward with respect to the plunger 100. This in turn causes follower flange 45 and follower 44 to move upward with respect to the cantilevered end of plunger arm 36. The upward movement of follower 44 latches follower 44 in a raised position and prevents it from discharging type element 118 from the stabber blade 110.

Operation of the ratchet mechanism is illustrated in FIGS. 3a and 3b. Referring to FIG. 3a, follower 44 supports ratchet 42. As ratchet 42 and follower 44 are raised, the notch in the uppermost end of ratchet 42 encounters ratchet deflector 48. This encounter rotates ratchet 42 in a clockwise direction, allowing one leg of the notch in the lower end of ratchet 42 to extend outward and above the ratchet latch 46.

At this point the plunger is fully extended to its lowest point and plunger arm 36 is likewise at its lowest point of travel.

Crank arm 24 is now at its lowest position. As the crank arm 24 continues to rotate, it begins its upstroke and moves the scotch yoke slider 27, support shaft 28, and plunger arm 36 upwardly. Upward movement of plunger arm 36 has no immediate effect upon plunger 100 except to allow soil spring 108 to act freely upon cap plate 106 and attempt to raise plunger tube 102. As plunger moves upward, the torsion spring 40 tends to move follower 44 downward with respect to the cantilevered end of plunger arm 36. Again referring to FIG. 3b, the follower moves downward with respect to ratchet latch 46 and ratchet latch 46 engages the notch in the lower end of ratchet 42. As the pivotal axis 43 of ratchet 42 and the extreme uppermost portion of ratchet latch 46 approach each other, the follower is retained in a latched-up or raised position.

As plunger arm 36 continues its upward movement, plunger push-pull bracket 54, having puller arm 58, engages the under side of the cap plate 106. This action assists the forces exerted by coil spring 108 on the underside of cap plate 106 and effectuates the retraction of plunger 100.

The arms of type element retainer spring 117 have a tendency to clamp inward at all times. Due to the friction between the two arms of type element retainer spring 117 and the edges of stabber blade 110, the type element 118 is removed from the type element carrier lug 122 and raised into its uppermost position of travel. The type element 118 is allowed to remain on stabber blade because the removal lugs 116 are in a retracted position and are not being forced downward by plunger rod 104 or the spring biased follower 44.

Plunger arm 36 continues to respond to the upward movement of scotch yoke slider 27 and support shaft 28 until such time as crank arm 24 is in its uppermost position of travel. At this time, the single cycle clutch 20 has completed its single revolution and is latched up and prevented from turning gear cam 22 and crank arm 24 any further.

At this point of operation, the typewriter type element carrier has returned to its change or home position, has been erected to a vertical position, the type element which was on the carrier has been removed, raised, and stored in a position under the carousel disc. At this time, the carousel disc is ready to be indexed to position the second desired type element on the carrier lug for subsequent typing operation.

The triggering or activation of the carousel addressing mechanism is accomplished in the following manner. Referring to FIG. 1, second gear/cam 30 has an offcenter lobe 29 on one face of the gear itself. The second gear/cam 30 is meshed with the first gear/cam 22. Gear/cam 22 has a step cam 21 on the face of the gear opposite that which the crank arm 24 is attached. Cam follower lever 296 has on its lower edge a protrusion 297 which serves as a cam follower on gear/cam 22. It also has a follower surface which contacts the lobe of gear/cam 30. This lever 296 is spring biased by follower lever spring 298 which urges the follower surfaces into contact with their respective cams. Gear/cam 22 and gear/cam 30 are designed to a diameter such that gear/cam 22 makes two complete revolutions for each complete revolution of gear/cam 30. Thus when the step on the cam of gear/cam 22 is in a top position, the follower surface of cam 296 would be capable of dropping into this notch. However, since gear/cam 30 rotates only one-half revolution for every revolution of gear/cam 22, the cam lobe of gear/cam 30 is positioned such that at the time described above the lobe on gear/cam 30 is either in an up or down position. At the beginning of the change cycle, the gear lobe of gear/cam 30 is rotated to its down position. This corresponds to that point in time when the first type element 118 (roman type font) has been removed from the carrier lug 122 and stored in a raised position under the carousel disc 66. At this point the follower lever 296 may move in a clockwise direction in response to the step cam 21 of gear/cam 22. Since the surface of the cam lobe 29 on gear cam 30 is such that the follower lever 296 is allowed to drop, the link 294 attached to cam follower lever 296 is activated.

The activation of link 294 thus initiates the release and selection of carousel 66. Referring to FIGS. 4 and 5, reset link 294 is connected to reset lever 290. Reset lever 290 pivots around pivot point 292. When reset link 294 is activated by follower lever 296 in FIG. 1, in response to the time position of gear/cams 22 and 30, the stop pawl reset lever 290 is rotated around its pivot point 292 and engages the lug 288 on the arm 286 of the stop pawl 272. Through the engagement of reset lever 290 with lug 288, stop pawl 272 is rotated about pivot 271. As stop pawl is rotated about 271, slot 273 engages latch lever pin 267 and causes latch lever 266 to move with stop pawl 272 around pivot 271. f

To select the proper type ball 118 to be installed with typewriter 10, a signal is generated either manually by a keyboard control 305 or by the control unit 304. This signal is directed to one of the several solenoids 254 and that selected solenoid attracts latch leaf 256 corresponding to the selected solenoid and as such allows the latch pawl 258, corresponding to the selected latch leaf 256, to rotate counterclockwise around its pivot point. Thus, the selected latch pawl 258 is allowed to rotate into position and contact the lip 264 of latch lever 266. As reset cable 294 activates lever 290 and causes latch lever 266 to pivot around its pivot point 271 as described earlier, the lip 264 is moved away from the pivot point for pawl 258 and slips into pawl notch 262. Torsion spring 260 rotates pawl 258 to capture lip 264 in pawl notch 262 as latch lever 266 is pivoted as described. When reset cable 294 is relaxed, latch lever 266 and stop pawl 272 are thus retained in a retracted position and stop pawl 272 disengages stop tab 250.

Referring to FIG. 1, drivebelt 68 is driven by drive pulley 276 which in turn is driven by worm gear 16. This driving pulley 70 slips with respect to drive belt 68 when the carousel disc 66 is in its latched position. When stop pawl 272 is retracted and carousel disc 66 is free to rotate, drivebelt 68, passing over idler pulleys 74 and through belt aperture 72, drives the disc pulley 70 causing carousel disc 66 to rotate in response to the rotation of worm gear 16.

As carousel disc 66 rotates, control lugs 252 rotate past the pawls 258. Only one pawl, 258, the selected pawl, extends into the path of any of the control lugs 252. As the control lug 252 which is in the same horizontal plane as the selected pawl 258 rotates toward the pawl, the lug 252 engages one arm of pawl 258, causing it to rotate against torsion spring 260 in a clockwise direction. This rotation unlatches latch lever 266, allowing it to rotate clockwise around its pivot point 271, thereby moving stop pawl 272 into position to engage the next succeeding stop tab 250. This unlatching action also serves to reset the selected latch leaf 256. As the italic type element will always be stored in the same position on carousel disc 66 and its position being known either to the operator or to the memory of the control unit 304, the appropriate solenoid is activated and the linkage operated in accordance with the above description, to select that type ball. The stop tab 250 which next engages stop pawl 272 corresponds to the italic type font type element and positions this element over type element carrier lug 122. At this time, carousel disc 66 ceases to rotate due to the interference between stop pawl 272 and stop tab 250, and drivebelt 68 begins slipping to prevent the belt from breaking.

At this point, stop pawl 252 has been moved along its long axis by the stop tab 250 engaging its lip. This movement is allowed, due to slots 273 and 276. As stop pawl 272 slides past latch lever pin 267 and pivot 271, stop pawl spring 274 is extended. Stop pawl spring 274 normally holds stop pawl position in its undisplaced disposition when stop pawl 272 is not in engagement with stop tab 250.

As stop pawl 272 is displaced by stop tab 250, its stop pawl cam surface 277 engages cam lever 278. As movement continues during the sliding of stop pawl 272 as described above, cam lever 278 rotates around its pivot thereby activating link 284 which in turn is connected to the control of cycle clutch 20. The activation of links 284 serves to activate cycle clutch 20 for the next succeeding operation of the plunger arm 36 and plunger mechanism 100. As the general operation of the cycle clutch 20, crank arm 24, scotch yoke slider 27, support shaft 28, and plunger arm 26 has been previously described and this operation is identical, it will not be repeated.

Through the above-described linkage, the cycle clutch, when operated, causes the plunger arm to move downward. This downward movement of plunger arm 36 moves ratchet mechanism 38 downward so that follower flange 45 may again engage the upper end of plunger rod 104. Likewise, plunger stub 56 will engage the cap plate 106 of plunger tube 102.

To control the ejection of the type element 118 from the stabber blade 110, a ratchet latch 38 is illustrated in FIGS. 2, 3a, and 3b. As follower flange 45 engages the upper end of plunger rod 104, follower 44 is moved upward. As seen in FIG. 3b, ratchet 42 is held at an angle with respect to the vertical by ratchet latch 46. As follower 44 moves upward ratchet deflector 48 engages the uppermost portion of ratchet 42, causing it to rotate slightly in a clockwise direction. By the time the ratchet deflector 48 engages ratchet 42, the ratchet has been displaced upward sufiiciently by the movement of follower 44 to clear ratchet latch 46 and allow the ratchet to revolve in a clockwise direction. This action releases ratchet 42 and when resistance is removed from follower flange 45 the follower 44 will be allowed to respond to the forces of torsion spring 40 and move downward. The downward movement of follower 44 will move the side of ratchet 42 into contact with ratchet latch 46 causing it to reorient again in a vertical position in readiness for the next latching operation.

As plunger stub 56 forces plunger downward, stabber blade 110, carrying type element 118, is inserted into the type element carrier lug slot 126. At this point the torsion spring 40 has caused follower 44 to move to its lowest position and has forced plunger rod 104 to move downward. Removal lugs 116 have been moved downward into contact with the top of type element 118.

As the cycle clutch and power transmission chain continue to operate through the rest of their remaining cycle, plunger arm 36 begins its upward movement. During the upward movement of plunger arm 36, torsion spring 40 continues to force follower 44 downward and keeps follower flange 45 against the upper end of plunger rod 104. At the same time plunger push-pull bracket 54 is moving upward with plunger arm 36. As the puller arm 58 of bracket 54 engages the underside of cap plate 106, the plunger mechanism 100 including the stabber plate 110 is moved upward in-response to the movement of plunger rod 36. The removal lugs 116 are remaining stationary due to the force of the torsion spring 40 acting through follower 44, push rod 104, and the removal lugs. As plunger 100 and stabber blade 110 move upward, the removal lugs effectively force the type element 118 to remain in position while the stabber blade is withdrawn. This allows the type element retainer spring 117 to flex inwardly and engage type element carrier grove 124 and thus retain the type element 118 in a position for subsequent typing. Thus, the type element ball for the italic type font has been placed on the carrier and the typewriter is prepared for typing of italics.

To return the roman font type element after completing the italic typing, this entire operation is repeated, the only change being that the carousel 66 would be indexed into position to replace the roman type element on the typewriter.

IMPRESSION SET CHANGE MECHANISM As different type fonts have different areas striking the ribbon of the typewriter and striking the paper and platen, different forces are required in order to provide a uniform copy.

Referring to FIG. 6, a separate figure illustrates the arrangement and operation of the impression set changer mechanism. Follower lever 140, in addition to activating the tilt pulley arm, as described earlier, is connected to link 154 which is in turn connected to bellcrank 156. The function of bellcrank 156 is strictly a change of direction and if a flexible cable is used, an idler pulley could be substituted. The following explanation will assume that bell crank 156 is the embodiment utilized. Link 158 extends from the output arm of bellcrank 156 to the input arm of bellcrank 160. The function of bellcrank 160 is two fold: the first being a change of direction, the second being to transmit this change of direction through plate 62. Connected to the output arm of bellcrank 160 is link 162, which extends to the upper arm of impression set lever 180. Impression set lever 180 is pivotally supported by attaching it to plate 162 through lever support 181.

As scotch yoke slider lug 144 moves with the scotch yoke slider 27, it bears against the camming surface 142 a follower lever 140. Follower lever 140 is rotated by the downward movement of scotch yoke slider 27 and acting through link 154, bellcrank 156, link 158, bellcrank 160, and link 162, pivots impression set lever 180 from its normally retracted position shown in FIG. 4 into approximately a vertical position when the scotch yoke slider is at its lowest point of travel illustrated in FIG. 6. As the impression set lever 182 is pulled into its vertical position, impression set link hook 183 engages impression control 198. The impression set link hook 183 is moved by the bellcranks and links enumerated above so that the impression control 198 is reset into the number one position on the impression control bracket 199.

An impression set trigger is provided for each type ball position. Each impression set trigger is attached to and mounted on the carousel disc 66 as shown in FIG. 6. This impression set trigger is manually adjustable and can be adjusted to provide the desirable impression setting for each type font used on the carousel. There is one of these impression set triggers 186 for each plunger position on the carousel disc 66. As each type font ball 1 18 is stored in a designated position on the carousel and does not move between positions, once the impression set trigger 186 is adjusted for any particular type font, it can remain in the adjustment until a type ball of a different type font is substituted.

To more clearly illustrate in more detail the impression set latch, FIG. 8 is provided. Referring to FIG. 8, impression set trigger 186 is illustrated as a dog extending into the path of knockoff cam 188. Knockoff cam 188 is pivotally attached and spring loaded to latch pawl 190. As the carousel disc 66 is fixed in position at this time in the cycle, latch mechanism 184 is moved in a direction equivalent to down in FIG. 8. As knockoff cam 188 passes the impression set trigger 186 it acts against torsion spring 192 to bypass impression set trigger 186 and then automatically restores to its operative position. This sequence causes the impression set lever hook 183 to engage impression control 198 and move it to the number one position in the impression control bracket 199. As the scotch yoke slider lug 144 rises in response to the scotch yoke slider 27 during the retraction portion of any cycle of the plunger 100, the impression set links and bellcranks act to rotate the impression set lever in the opposite direction, causing the lower end to swing up and out of the way.

During this movement, the impression set link hook 183 is likewise pivoted and moves the impression control 198 to another position within the impression control bracket 199. This other position is determined by the location of impression set trigger 186 with respect to knockoff cam 188. As can be seen in FIG. 8, knockoff cam 188 will positively engage impression set trigger 186 and cause latch pawl 190 to rotate about its pivot axis in a counterclockwise direction, effectuating the release of latch 196. When latch 196 is released, the spring tension inherent in impression control 198 causes the impression set link 182 to respond by rotating in a counterclockwise direction caused by the force of impression control 198 against impression set link hook 183. This rotation of the impression set link hook allows first the impression control 198 to snap back into a preselected position within the impression control bracket 199 and secondly allows the impression set link hook 183 to disengage from impression control 198. As impression set lever 180 continues to rotate about its pivot point 204 in response to the movement of the scotch yoke slider lug 144, the impression set link hook 183 interferes with camming surface 202 on reset cam 200. This forces impression set link hook 183 to rotate in a counterclockwise direction and reset latch 196 under the control of latch pawl 190. The above sequence would take place during the removal phase of the type ball of type element from the typewriter. The entire impression setting sequence would then be repeated in response to the second up-down movement of the scotch yoke slider 27 when the italics type ball of the example is placed on the type element carrier lug 122. i

As can be seen when the italics type element 118 is placed over carrier lug 122 and readied for positioning on carrier lug 122, the appropriate impression set trigger 186 for the italic type font would be in position to control and interact with knockoff cam 188, thereby effecting the preselected and appropriate setting of impression control 198 for the italics type font.

FIG. 7 illustrates the relationship between impression set link hook 183 with the impression control 198 and the impression control bracket 199.

It is recognized that in disclosing a preferred embodiment of the invention that some mechanisms may be illustrated as bellcranks, links, cables, and levers, but it is recognized that these devices could be interchanged with links or push-pull cables of the type which provide the desired direction and amount of motion in response to the initiating force and movement.

Likewise, in some respects mechanical latch linkages could be changed to electromechanical mechanisms such as solenoids of electronic actuators. Although the type element removal mechanism is disclosed as mechanically activated and supported on a indexable carousel, it is recognized that the removal mechanism could equally well be manually operated and entirely separate. In that embodiment the removal lugs would be operated by a pushbutton on the top of a shortened plunger tube 102 and all other aspects of the stabber blade 110, removal lugs 116, and guide cap 114 would be the same.

What is claimed is: I

1. A type element installation and removal mechanism for use with type elements of a single element typewriter comprising:

a single type element having dual arm retainer spring means, said dual arm retainer spring means for retaining said type element on said typewriter;

a slot in the tip of said type element, said slot oriented transselected. 5. An apparatus for changing type elements on a single element typewriter comprising:

means for positioning the type element at a predesignated verse to the arms of said dual arm retainer spring means; change position;

a stabber means for entering said slot, said stabber means means for erecting said type element to a vertical position having camming means for spreading the arms of said after said type element has been positioned at said spring means, removal means slideably supported adpredesignated change position; jacent said stabber means, to engage and eject said type means for inserting a removal means into said type element element from said stabber means. to release said element from a carriage holding said type 2. An automatically selectably changeable type font element;

typewriting apparatus comprising: means for removing said type element from said typewriter,

a single type element typewriter; and storing said type element on an indexable positioning an indexable positioning means for selectably positioning means, said removal and storage means positioned above type elements, said positioning means positioned above 15 said typewriter and carried by said indexable positioning said typewriter; means;

an index control means for controlling said indexable posimeans for indexing said indexable positioning means to a tioning means; second position, for replacing a second type element on a plurality of reciprocating installation and removal means said typewriter;

carried by said positioning means for installing and and means for adjusting the impression control of said removing said type elements with respect to a carrier typ wri er to a pr l po i i n. said po iti n rwhich holds the type element in u e at any time in the responding to the impression requirements of said second typewriter, and for storing said elements not being used type elem nton said positioning means; 6. The method of changing type elements on a single elesaid typewriter having a moving type element and a 5 ment typewriter comprising the steps of:

predetermined type element change position; positioning the type element to a predesignated change thereby providing a changing apparatus for removal, instal- P s t lation and storing of type elements on a single element erecting said type element toavertical positi n; typewriter. inserting a removal means into said type element to release 3. An automatically selectabl changeable type f said element, removing said type element from said typewriter as in claim 2, further comprising a magnetic record yp responsive control means, said typewriter, said index control oring aid type element on a indexable positioning means; means, and said installation and r m val me being indexing said indexable positioning-means to asecond positrolled by said magnetic record responsive control means. tion} 4. An automatically selectable changeable type font mstaumgasecond f elejmem YP typewriter as in claim 2 further comprising: and simultaneously ad usting the impression control of said an impression set means responsive to the position of said typewmfir to a f f f positioning means and engageable with Said indexable responding to the impression requirements of said second positioning means to adjust the impression control means type elementof said typewriter for each selected type element as 40 

1. A type element installation and removal mechanism for use with type elements of a single element typewriter comprising: a single type element having dual arm retainer spring means, said dual arm retainer spring means for retaining said type element on said typewriter; a slot in the tip of said type element, said slot oriented transverse to the arms of said dual arm retainer spring means; a stabber means for entering said slot, said stabber means having camming means for spreading the arms of said spring means, removal means slideably supported adjacent said stabber means, to engage and eject said type element from said stabber means.
 2. An automatically selectably changeable type font typewriting apparatus comprising: a single type element typewriter; an indexable positioning means for selectably positioning type elements, said positioning means positioned above said typewriter; an index control means for controlling said indexable positioning means; a plurality of reciprocating installation and removal means carried by said positioning means for installing and removing said type elements with respect to a carrier which holds the type element in use at any time in the typewriter, and for storing said elements not being used on saId positioning means; said typewriter having a moving type element and a predetermined type element change position; thereby providing a changing apparatus for removal, installation and storing of type elements on a single element typewriter.
 3. An automatically selectably changeable type font typewriter as in claim 2, further comprising a magnetic record responsive control means, said typewriter, said index control means, and said installation and removal means being controlled by said magnetic record responsive control means.
 4. An automatically selectable changeable type font typewriter as in claim 2 further comprising: an impression set means responsive to the position of said positioning means and engageable with said indexable positioning means to adjust the impression control means of said typewriter for each selected type element as selected.
 5. An apparatus for changing type elements on a single element typewriter comprising: means for positioning the type element at a predesignated change position; means for erecting said type element to a vertical position after said type element has been positioned at said predesignated change position; means for inserting a removal means into said type element to release said element from a carriage holding said type element; means for removing said type element from said typewriter, and storing said type element on an indexable positioning means, said removal and storage means positioned above said typewriter and carried by said indexable positioning means; means for indexing said indexable positioning means to a second position, for replacing a second type element on said typewriter; and means for adjusting the impression control of said typewriter to a preselected position, said position corresponding to the impression requirements of said second type element.
 6. The method of changing type elements on a single element typewriter comprising the steps of: positioning the type element to a predesignated change position; erecting said type element to a vertical position; inserting a removal means into said type element to release said element, removing said type element from said typewriter; storing said type element on a indexable positioning means; indexing said indexable positioning means to a second position; installing a second type element on said typewriter; and simultaneously adjusting the impression control of said typewriter to a preselected position, said position corresponding to the impression requirements of said second type element. 